intermittant problem

Sometimes when I start to execute a program the spindle will start up and then the axis's jump then spindle slows down and keeps jumping and slowing down this till I stop the program. If I start the spindle manually before the program runs the stop start jumping does not happen.

Symptoms do not appear when I first switch on the machine and I can run a program a few times before the problem appears but once it happens I have to manually start the spindle.

I did think it might be a heat issue but none of the drivers seem to be too hot so I'm thinking it might be an amps issue.

Any ideas ?

Bill

Thanks Andy I'll try to check it out.

Bill